Not all compost tests are the same - TPS Lab offers two different tests for the essential qualities of compost:

Active Organic Matter - This measures the amount of organic matter that has been decomposed or digested by microbes into useable material by plants.

Loss On Ignition (LOI) measures the total organic matter content that is useful indetermining how much raw organic matter is available for microbial food to digest into plant-available nutrients.

U.S. Composting Council

TPS Lab is the 11th approved US Composting Council Seal of Testing Assurance ( USCC STA ) laboratory for all participating STA composters in the United States and Canada! You can find us listed at http://compostingcouncil.org/labs/.


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